I also wonder if we will ever see a dino 110??
75W-140 in a Mustang.....Why?
- Thread starter Unleashedbeast
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Originally Posted By: Unleashedbeast
Hmmm, I'm considering the 75W-110 as Amsoil said it gives you an "in between" performance of 75W-90 and 75W-140
You should research Heavy Shockproof. Film strength of a 75W-250, fluid friction and viscosity of a 75W-90.
Hmmm, I'm considering the 75W-110 as Amsoil said it gives you an "in between" performance of 75W-90 and 75W-140
You should research Heavy Shockproof. Film strength of a 75W-250, fluid friction and viscosity of a 75W-90.
Originally Posted By: brandini
you're concerned with fuel economy in a mustang?
you bought the wrong car
I got 20 mpg City and 27 mpg Highway out of my 2007 in 12.9 Trim.
Im getting 23 mpg City out of my 2011 with 416 bhp (412 bhp represents 1% derating of actual J1349 results).
These cars may do a little better than you think in the real world. We are not forced to drive them like they have no torque like the official EPA Test Cycle.
you're concerned with fuel economy in a mustang?
you bought the wrong car
I got 20 mpg City and 27 mpg Highway out of my 2007 in 12.9 Trim.
Im getting 23 mpg City out of my 2011 with 416 bhp (412 bhp represents 1% derating of actual J1349 results).
These cars may do a little better than you think in the real world. We are not forced to drive them like they have no torque like the official EPA Test Cycle.
Originally Posted By: SuperDave456
I wonder if you will get noise if you switch to a lighter fluid.
It would be an Interesting test.
Is there something different about this 8.8" differential than the 8.8" Ford has been making for decades? For years the 8.8" was found in trucks, police cars, limos, and Mustangs...all with 80w90. I realize none of those vehicles had the HP of this 2008 mustang, so that may explain the difference.
The conservative choice is to run the recommended 75w140. I doubt you would be able to measure any fuel economy improvement anyway, especially in FL.
I wonder if you will get noise if you switch to a lighter fluid.
It would be an Interesting test.
Is there something different about this 8.8" differential than the 8.8" Ford has been making for decades? For years the 8.8" was found in trucks, police cars, limos, and Mustangs...all with 80w90. I realize none of those vehicles had the HP of this 2008 mustang, so that may explain the difference.
The conservative choice is to run the recommended 75w140. I doubt you would be able to measure any fuel economy improvement anyway, especially in FL.
My guess as to why Ford uses a 140 grade in a car goes thusly:
1) Consolidation. Only one oil to stock for most applications. A syn 75W140 offers protection in a wider range of temperatures without much of a fuel economy penalty. Cold weather performance would be good too... better than a dino 80W90.
My opinion is that the 8.8 axle in a late-model 'Stang would do fine with a 90 grade oil, as many 8.8 axles have used since they debuted in the early '80s (it's 8.5 and 8.6-inch ancestors appeared in the late 1970s). If it were mine, and I was considering a change, I would do a pseudo-scientific test and install a diff temp gauge to observe oil temps for a year or so. If they generally stay below that 212F viscosity rating temp, I might consider a move to a syn 75W90.If the diff runs consistently below 180 degrees, it's likely you would see an upwards blip in fuel economy by running a 90 grade oil. Some vehicles have noted a 1 mpg increase just going from an older generation, nothin' special gear oil to a syn. I noted a drop of 10-15 degrees in axle oil temp going from a syn 75W140 to a dino 80W90 in a Ford truck axle (a necessary change for an aftermarket limited slip application), something I can only attribute to a drop in fluid friction with a lighter oil (at operating temp). My diff temps generally run below 180 as well but I'm still figuring that drop in temp out!
All this said, however, it's hardly worth the effort unless you just want to play and learn (as I have). More and more as I play with stuff, I find the OE does a pretty good job of selecting the viscosities of their lubricants... as least in the narrow range of stuff I've played with. I could argue with some of the products themselves. That's where the bean counters come in, but the engineers still dictate the viscosities.
1) Consolidation. Only one oil to stock for most applications. A syn 75W140 offers protection in a wider range of temperatures without much of a fuel economy penalty. Cold weather performance would be good too... better than a dino 80W90.
My opinion is that the 8.8 axle in a late-model 'Stang would do fine with a 90 grade oil, as many 8.8 axles have used since they debuted in the early '80s (it's 8.5 and 8.6-inch ancestors appeared in the late 1970s). If it were mine, and I was considering a change, I would do a pseudo-scientific test and install a diff temp gauge to observe oil temps for a year or so. If they generally stay below that 212F viscosity rating temp, I might consider a move to a syn 75W90.If the diff runs consistently below 180 degrees, it's likely you would see an upwards blip in fuel economy by running a 90 grade oil. Some vehicles have noted a 1 mpg increase just going from an older generation, nothin' special gear oil to a syn. I noted a drop of 10-15 degrees in axle oil temp going from a syn 75W140 to a dino 80W90 in a Ford truck axle (a necessary change for an aftermarket limited slip application), something I can only attribute to a drop in fluid friction with a lighter oil (at operating temp). My diff temps generally run below 180 as well but I'm still figuring that drop in temp out!
All this said, however, it's hardly worth the effort unless you just want to play and learn (as I have). More and more as I play with stuff, I find the OE does a pretty good job of selecting the viscosities of their lubricants... as least in the narrow range of stuff I've played with. I could argue with some of the products themselves. That's where the bean counters come in, but the engineers still dictate the viscosities.
Originally Posted By: Rob_Roy
For years the 8.8" was found in trucks, police cars, limos, and Mustangs...all with 80w90
Not all and not always It's hard to follow all of them unless you are professionally involved, but there were some issues here and there, like when they change materials, e.g. shaft alloy composition, etc. Even in maintenance manual there were 2 options for them: 80w90 and 75w140 syn - at the very back of the book
For years the 8.8" was found in trucks, police cars, limos, and Mustangs...all with 80w90
Not all and not always It's hard to follow all of them unless you are professionally involved, but there were some issues here and there, like when they change materials, e.g. shaft alloy composition, etc. Even in maintenance manual there were 2 options for them: 80w90 and 75w140 syn - at the very back of the book
Originally Posted By: Shuttler
Originally Posted By: Rob_Roy
For years the 8.8" was found in trucks, police cars, limos, and Mustangs...all with 80w90
Not all and not always It's hard to follow all of them unless you are professionally involved, but there were some issues here and there, like when they change materials, e.g. shaft alloy composition, etc. Even in maintenance manual there were 2 options for them: 80w90 and 75w140 syn - at the very back of the book
Welcome to the site.
As for my comment on the 8.8", I wasn't saying they were all the same, I was asking. Thanks for pointing out the differences. As for the 80w90, I was thinking of the factory fill on earlier axles. Are you saying that 75w140 was sometimes used on axles produced in the 80's and 90's? I'm also curious when 75w140 first appeared in the maintenance manuals for the 8.8"
To complicate things more, didn't Ford back-spec 75w140 to some vehicles? Our 2003 Lincoln Navigator calls for 75w90 in the owners manual, but the rear end was rebuilt under warranty and now has a 75w140 tag on the rear cover.
Originally Posted By: Rob_Roy
For years the 8.8" was found in trucks, police cars, limos, and Mustangs...all with 80w90
Not all and not always It's hard to follow all of them unless you are professionally involved, but there were some issues here and there, like when they change materials, e.g. shaft alloy composition, etc. Even in maintenance manual there were 2 options for them: 80w90 and 75w140 syn - at the very back of the book
Welcome to the site.
As for my comment on the 8.8", I wasn't saying they were all the same, I was asking. Thanks for pointing out the differences. As for the 80w90, I was thinking of the factory fill on earlier axles. Are you saying that 75w140 was sometimes used on axles produced in the 80's and 90's? I'm also curious when 75w140 first appeared in the maintenance manuals for the 8.8"
To complicate things more, didn't Ford back-spec 75w140 to some vehicles? Our 2003 Lincoln Navigator calls for 75w90 in the owners manual, but the rear end was rebuilt under warranty and now has a 75w140 tag on the rear cover.
Rob, if this link works it shows all of Fords recommendations and what year models.
http://www.fcsdchemicalsandlubricants.com/Main/quickref/axlelube.pdf
http://www.fcsdchemicalsandlubricants.com/Main/quickref/axlelube.pdf
Isn't the ring gear a bit small for the power produced?
Add this to the hard use expected, and we know why a heavier lube is spec'd.
Add this to the hard use expected, and we know why a heavier lube is spec'd.
Originally Posted By: Ben99GT
Originally Posted By: Unleashedbeast
Hmmm, I'm considering the 75W-110 as Amsoil said it gives you an "in between" performance of 75W-90 and 75W-140
You should research Heavy Shockproof. Film strength of a 75W-250, fluid friction and viscosity of a 75W-90.
That's the other gear oil I would be considering (along with the Amsoil SG 110), IF I felt fully confident about synthetics in an Eaton clutchpack type limited slip.
I figure Jim Allen has that same lack of confidence as well, since he used dino in his app.
Originally Posted By: Unleashedbeast
Hmmm, I'm considering the 75W-110 as Amsoil said it gives you an "in between" performance of 75W-90 and 75W-140
You should research Heavy Shockproof. Film strength of a 75W-250, fluid friction and viscosity of a 75W-90.
That's the other gear oil I would be considering (along with the Amsoil SG 110), IF I felt fully confident about synthetics in an Eaton clutchpack type limited slip.
I figure Jim Allen has that same lack of confidence as well, since he used dino in his app.
Originally Posted By: dailydriver
That's the other gear oil I would be considering (along with the Amsoil SG 110), IF I felt fully confident about synthetics in an Eaton clutchpack type limited slip.
I figure Jim Allen has that same lack of confidence as well, since he used dino in his app.
No, I have no lack of confidence in synthetics, but was given a strong recommendation against synthetic by an engineer at the company who makes my limited slip, namely Auburn Gear. Bear in mind it's a cone clutch design and uses no clutch plates in it's design.
Despite the warnings to use only mineral oil, I was all ready to install some syn after a few thousand miles of break in. I knew it would effect the bias ratio of the unit but wasn't aware of any other potential problems. Luckily, I was given the opportunity to consult one of their engineers... not one of the regular "phone" guys, but a real one one that sits in a desk surrounded by CAD drawings taped to the walls and parts on shelves around his desk. Anyway, the metallurgy and surface prep of the cone and it's pocket were designed around the characteristics of mineral oil. Synthetic oil significantly reduces friction and thus reduces the bias ratio of the unit. The "but" is that there is also a permanent "polishing" effect on the friction surfaces of the cone and the pocket when synthetic is used and that further reduces the bias ratio (at least until the unit is disassembled and the surfaces are roughed up). This is why I am using a mineral oil. There is some lubricant research being done at Auburn and perhaps I'll be allowed some access to that when it's complete and give you guys the skinny.
Mectech2: The 8.8 inch ring gear is actually about right, maybe a little overkill, for the power of a Mustang. With only a few exceptions 8-9 inch ring gears have ably served muscle cars since the dawn of time. The equation is really a about traction torque and weight. We know the car has one of those in abundance but if the car is light, it's not much of an issue. The deadly combo is lots of traction torque and lots of weight. That's why I recommended a diff temp gauge above as a guide. You soon see how hard the axle is working. If you take car "X" at a specific weight with an 8.8 inch ring gear and record the diff temp, then swap it for a 7.5 inch ring gear, you will see a significant increase in diff oil temp at any load. It's just a case of the same load being spread over less surface area of the ring gear teeth.
AFAIK, the 9.75 inch Dana 60 was the biggest factory installed ring gear size used in cars, namely Mopar muscle cars of the '60s. Besides the familiar 8.8 Ford, 8.75 Mopar, 8.5/8.6 GM, 8.875 GM (12-bolt), 9-inch Ford, there were some 9.38-inch Ford dropouts in Lincolns and some 8.75, 9.30 and 9.375s in big Olds, Buicks and Pontiacs. There may have been a couple of years when the 9.25 Mopar was used in the last of the big Chryslers, but I'd have to look that up. Those are the biggest ring geared axles I know of in cars and they mostly appeared in the biggest, heaviest cars, or in muscle cars. In general, the lighter the car, the smaller the ring gear... even with a fairly high power-to-weight ratio.
That's the other gear oil I would be considering (along with the Amsoil SG 110), IF I felt fully confident about synthetics in an Eaton clutchpack type limited slip.
I figure Jim Allen has that same lack of confidence as well, since he used dino in his app.
No, I have no lack of confidence in synthetics, but was given a strong recommendation against synthetic by an engineer at the company who makes my limited slip, namely Auburn Gear. Bear in mind it's a cone clutch design and uses no clutch plates in it's design.
Despite the warnings to use only mineral oil, I was all ready to install some syn after a few thousand miles of break in. I knew it would effect the bias ratio of the unit but wasn't aware of any other potential problems. Luckily, I was given the opportunity to consult one of their engineers... not one of the regular "phone" guys, but a real one one that sits in a desk surrounded by CAD drawings taped to the walls and parts on shelves around his desk. Anyway, the metallurgy and surface prep of the cone and it's pocket were designed around the characteristics of mineral oil. Synthetic oil significantly reduces friction and thus reduces the bias ratio of the unit. The "but" is that there is also a permanent "polishing" effect on the friction surfaces of the cone and the pocket when synthetic is used and that further reduces the bias ratio (at least until the unit is disassembled and the surfaces are roughed up). This is why I am using a mineral oil. There is some lubricant research being done at Auburn and perhaps I'll be allowed some access to that when it's complete and give you guys the skinny.
Mectech2: The 8.8 inch ring gear is actually about right, maybe a little overkill, for the power of a Mustang. With only a few exceptions 8-9 inch ring gears have ably served muscle cars since the dawn of time. The equation is really a about traction torque and weight. We know the car has one of those in abundance but if the car is light, it's not much of an issue. The deadly combo is lots of traction torque and lots of weight. That's why I recommended a diff temp gauge above as a guide. You soon see how hard the axle is working. If you take car "X" at a specific weight with an 8.8 inch ring gear and record the diff temp, then swap it for a 7.5 inch ring gear, you will see a significant increase in diff oil temp at any load. It's just a case of the same load being spread over less surface area of the ring gear teeth.
AFAIK, the 9.75 inch Dana 60 was the biggest factory installed ring gear size used in cars, namely Mopar muscle cars of the '60s. Besides the familiar 8.8 Ford, 8.75 Mopar, 8.5/8.6 GM, 8.875 GM (12-bolt), 9-inch Ford, there were some 9.38-inch Ford dropouts in Lincolns and some 8.75, 9.30 and 9.375s in big Olds, Buicks and Pontiacs. There may have been a couple of years when the 9.25 Mopar was used in the last of the big Chryslers, but I'd have to look that up. Those are the biggest ring geared axles I know of in cars and they mostly appeared in the biggest, heaviest cars, or in muscle cars. In general, the lighter the car, the smaller the ring gear... even with a fairly high power-to-weight ratio.
Originally Posted By: Rob_Roy
Welcome to the site.
Thank you.
Sorry for the belated reply. I am not a frequent Net user. As for your question: I do not remember off the top of my head. Need to look up in TSB archives somewhere. In any event, factory fill by Ford in recent (2004+) panthers is of very high quality. Most people who are good on the maintenance overdo and drain it too soon. Any experience with Mobilube 1 SHC?
Welcome to the site.
Thank you.
Sorry for the belated reply. I am not a frequent Net user. As for your question: I do not remember off the top of my head. Need to look up in TSB archives somewhere. In any event, factory fill by Ford in recent (2004+) panthers is of very high quality. Most people who are good on the maintenance overdo and drain it too soon. Any experience with Mobilube 1 SHC?
Provided my memory is correct, all of the panther platform cars I have owned (89 Marquis, 97 P71,98 P71,99 P71,01 Marquis)called for 80w90 in the manual. The 2004 P71 my uncle uses for a parts runner calls for 75w140. I don't know what Ford recommends for a drain interval, but I can say that the '04 had 100k on it when we purchased it, and the oil was nasty. The oil was coal black, there was plenty of metal on the magnet, and the LS chattered on tight turns. I can't say for certain that the oil was the factory-fill, but the rear cover did not look like it had been disturbed. The gears & bearings looked fine, so I refilled the differential with 75w140 and it has been quiet and smooth ever since.
I have not used Mobilube 1 SHC personally, but it looks like a high quality gear lube. I would guess it is popular for Eaton applications with an extended warranty.
I have not used Mobilube 1 SHC personally, but it looks like a high quality gear lube. I would guess it is popular for Eaton applications with an extended warranty.
Trucks with Synthetic - Lubed for Life
Mustangs with Synthetic - 150,000 Mile
Cars in Police, Taxi or Livery Service with Syntheitc - 100,000 mile. Inspect for condition. Change may be waived if factory filled with 75W140 Synthetic.
Mustangs with Synthetic - 150,000 Mile
Cars in Police, Taxi or Livery Service with Syntheitc - 100,000 mile. Inspect for condition. Change may be waived if factory filled with 75W140 Synthetic.
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It still cracks me up that GM put a 10 bolt 7.5" rear end in the 1998-2002 Trans Am and Camaro. Crank HP were in excess of 325 and one good launch with sticky tires was all it took to break a ring gear.
Great idea GM!
Great idea GM!
Originally Posted By: Unleashedbeast
It still cracks me up that GM put a 10 bolt 7.5" rear end in the 1998-2002 Trans Am and Camaro. Crank HP were in excess of 325 and one good launch with sticky tires was all it took to break a ring gear.
Great idea GM!
Well, I could not agree with you more on that, and it is one of the ONLY criticisms I have of GM as concerns MY car.
But mine has actually been just fine, probably due to few all out drag strip launches on sticky tires/track, keeping power just over stock with minimal engine mods, mostly road course/autocross use (as far as racing abuse goes), and maniacal rear axle maintenance/excessively OCD fluid changes.
FYI; Many (if not MOST) LS1 f bodies made 325 hp (or more) TO THE WHEELS!
It still cracks me up that GM put a 10 bolt 7.5" rear end in the 1998-2002 Trans Am and Camaro. Crank HP were in excess of 325 and one good launch with sticky tires was all it took to break a ring gear.
Great idea GM!
Well, I could not agree with you more on that, and it is one of the ONLY criticisms I have of GM as concerns MY car.
But mine has actually been just fine, probably due to few all out drag strip launches on sticky tires/track, keeping power just over stock with minimal engine mods, mostly road course/autocross use (as far as racing abuse goes), and maniacal rear axle maintenance/excessively OCD fluid changes.
FYI; Many (if not MOST) LS1 f bodies made 325 hp (or more) TO THE WHEELS!
Originally Posted By: Jim Allen
Originally Posted By: dailydriver
That's the other gear oil I would be considering (along with the Amsoil SG 110), IF I felt fully confident about synthetics in an Eaton clutchpack type limited slip.
I figure Jim Allen has that same lack of confidence as well, since he used dino in his app.
No, I have no lack of confidence in synthetics, but was given a strong recommendation against synthetic by an engineer at the company who makes my limited slip, namely Auburn Gear. Bear in mind it's a cone clutch design and uses no clutch plates in it's design.
Despite the warnings to use only mineral oil, I was all ready to install some syn after a few thousand miles of break in. I knew it would effect the bias ratio of the unit but wasn't aware of any other potential problems. Luckily, I was given the opportunity to consult one of their engineers... not one of the regular "phone" guys, but a real one one that sits in a desk surrounded by CAD drawings taped to the walls and parts on shelves around his desk. Anyway, the metallurgy and surface prep of the cone and it's pocket were designed around the characteristics of mineral oil. Synthetic oil significantly reduces friction and thus reduces the bias ratio of the unit. The "but" is that there is also a permanent "polishing" effect on the friction surfaces of the cone and the pocket when synthetic is used and that further reduces the bias ratio (at least until the unit is disassembled and the surfaces are roughed up). This is why I am using a mineral oil. There is some lubricant research being done at Auburn and perhaps I'll be allowed some access to that when it's complete and give you guys the skinny.
I was not questioning your (or even my) confidence in synthetic gear oils in general, just in our specific applications (i.e.; if I knew there would be NO problems, synthetic would already be in there!)
I forgot you had the Auburn unit.
The Eaton tech I spoke to yesterday, albeit maybe not as much of an 'engineering doctorate type' as the Auburn tech you last spoke to, told me he has had MANY customers call in and tell him that their carbon fiber clutchpack diffs chattered like crazy when they used synthetic gear oils.
This, combined with not being able to test all of the thousands of synthetics out there in their diffs is what forces them to require mineral based gear oils in this unit.
That being said, he was the FIRST one there I've spoken to who has actually said that one could try a synthetic gear oil in this unit and IF it does not; chatter, one-wheel peel, or make funky noises, then you're good to go.
He also mentioned that he gets at least 25 calls a day about this very subject (and man, that must get tiresome REAL quick!).
Originally Posted By: dailydriver
That's the other gear oil I would be considering (along with the Amsoil SG 110), IF I felt fully confident about synthetics in an Eaton clutchpack type limited slip.
I figure Jim Allen has that same lack of confidence as well, since he used dino in his app.
No, I have no lack of confidence in synthetics, but was given a strong recommendation against synthetic by an engineer at the company who makes my limited slip, namely Auburn Gear. Bear in mind it's a cone clutch design and uses no clutch plates in it's design.
Despite the warnings to use only mineral oil, I was all ready to install some syn after a few thousand miles of break in. I knew it would effect the bias ratio of the unit but wasn't aware of any other potential problems. Luckily, I was given the opportunity to consult one of their engineers... not one of the regular "phone" guys, but a real one one that sits in a desk surrounded by CAD drawings taped to the walls and parts on shelves around his desk. Anyway, the metallurgy and surface prep of the cone and it's pocket were designed around the characteristics of mineral oil. Synthetic oil significantly reduces friction and thus reduces the bias ratio of the unit. The "but" is that there is also a permanent "polishing" effect on the friction surfaces of the cone and the pocket when synthetic is used and that further reduces the bias ratio (at least until the unit is disassembled and the surfaces are roughed up). This is why I am using a mineral oil. There is some lubricant research being done at Auburn and perhaps I'll be allowed some access to that when it's complete and give you guys the skinny.
I was not questioning your (or even my) confidence in synthetic gear oils in general, just in our specific applications (i.e.; if I knew there would be NO problems, synthetic would already be in there!)
I forgot you had the Auburn unit.
The Eaton tech I spoke to yesterday, albeit maybe not as much of an 'engineering doctorate type' as the Auburn tech you last spoke to, told me he has had MANY customers call in and tell him that their carbon fiber clutchpack diffs chattered like crazy when they used synthetic gear oils.
This, combined with not being able to test all of the thousands of synthetics out there in their diffs is what forces them to require mineral based gear oils in this unit.
That being said, he was the FIRST one there I've spoken to who has actually said that one could try a synthetic gear oil in this unit and IF it does not; chatter, one-wheel peel, or make funky noises, then you're good to go.
He also mentioned that he gets at least 25 calls a day about this very subject (and man, that must get tiresome REAL quick!).
changed the rear diff fluid to Amsoil Severe Gear 75W-110
This could be the placebo effect but...
Car seems to require less throttle to maintain certain speeds, or to achieve a certain speed. Although, I would assume the difference would have been to minor to notice.
This could be the placebo effect but...
Car seems to require less throttle to maintain certain speeds, or to achieve a certain speed. Although, I would assume the difference would have been to minor to notice.
That could be just from fresh fluid, combined with placebo effect. I noticed a little of the same when I changed the rear diff fluid to 75W-140 Mobil 1 in my Jeep yesterday. It had either 80W-90 or 75W-140 in there before, not sure which.
Reviving an older thread.
With the release of the 2013 GT500, Ford now specs a 75W-90 full synthetic lubricant in the rear differential, despite if it has the performance package or not.
The standard package includes a clutch pack type differential with no external oil cooler. 2 quart capacity
The performance package includes the Torsen gear type differential with an external oil cooler. 3 quart capacity
No matter which setup you buy, Ford recommends 75W-90 synthetic gear lube. It's still an 8.8" ring gear and this car is the most powerful production Mustang in history.
Explain that!
With the release of the 2013 GT500, Ford now specs a 75W-90 full synthetic lubricant in the rear differential, despite if it has the performance package or not.
The standard package includes a clutch pack type differential with no external oil cooler. 2 quart capacity
The performance package includes the Torsen gear type differential with an external oil cooler. 3 quart capacity
No matter which setup you buy, Ford recommends 75W-90 synthetic gear lube. It's still an 8.8" ring gear and this car is the most powerful production Mustang in history.
Explain that!
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